Heat-developable reproduction material



United States Patent 3,434,838 HEAT-DEVELOPABLE REPRODUCTION MATERIALJohannes Munder and Giinther Hertzberg, Wiesbaden- Biebrich, Germany,assignors, by mesne assignments, to

Keuf'tel & Esser Company, Hoboken, NJ.

No Drawing. Filed Feb. 24, 1965, Ser. No. 435,027 Claims priority,application Germany, Feb. 29, 1964, K 52,254 Int. Cl. G03c 1/58 US. Cl.96-75 8 Claims ABSTRACT OF THE DISCLOSURE A heat-developable diazotypereproduction material is prepared by impregnating, during thepaper-making process, a paper carrier sheet with a heat-active source ofalkaline material, such as urea. Upon completion of the paper-makingprocess, the impregnated paper sheet is coated with a compositionincluding a light-sensitive diazonium compound and a coupler compoundcapable of forming an azo dye with such diazoniurn compound in analkaline medium. Heating of the resulting sheet material creates analkaline medium conducive to the coupling reaction between the diazoniumand the azo coupler compounds and effects development of an azo dye.

The present invention relates to reproduction materials and refers moreparticularly to a heat-developable twocomponent diazotype reproductionmaterial.

For the preparation of photocopies according to the diazotype copyingprocess, two methods are used: the dry process and the semi-wet process.In the dry process, the copying material includes a diazo compound andan azo coupling component, and development is effected with ammonia gas.In the semi-wet process, the copying material includes a diazo compoundand development is effected in acid or alkaline solution with an azocoupling component to form an azo dye in the unexposed areas.

One disadvantage in the conventional development of such photocopies isthe unpleasant odor caused by the ammonia used in the dry process andthe inconvenient use of a liquid bath in the semi-wet process.Consequently, since the introduction of the diazotype process, attemptshave been made in the art to initiate dye formation by the action ofsteam or heat.

The coupling process with phenols proceeds smoothly only in alkaline toneutral pH-range. Accordingly, prior attempts were directed to a pHshift by temperature increase with the optional use of suitableadditives. This pH shift can be achieved by removal of a volatile acidor by generating alkaline substances from non-alkaline substances.Additives causing the pH shift were generally applied in specialcoatings between the light-sensitive composition and the support of thecoating, or to the side away from the light-sensitive coating. Onedisadvantage is the deleterious effect on the shelf life of the copyingmaterial or the impaired quality of the copies produced.

Therefore, one object of the present invention is to provide aheat-developable, two-component diazotype reproduction material whichovercomes these disadvantages.

Another object is to provide a heat-developable reproduction materialhaving excellent shelf life with excellent quality in the photocopiesproduced therefrom.

Other objects will be apparent in the course of the followingspecification.

The object of the present invention may be realized by providing aheat-developable, two-component diazotype copying material comprising asupport and a light-sensitive coating on the support, the supportcontaining at least one compound which under the action of heat pro-3,434,838 Patented Mar. 25, 1969 duces a neutral or alkaline environmentsuitable for development in the light-sensitive coating.

The preparation of the present copying material comprises the step ofimpregnating a support with at least one compound, with or withoutadditives, which under the action of heat produces a neutral or alkalineenvironment in the light-sensitive coating.

Materials commonly employed in diazotype techniques are suitable assupport materials. It has proved advantageous to choose a support thatis permeable to the compound which creates the environment in thelight-sensitive mixture. Supports which fulfill this requirement arepreferably paper with weights of 50 to grams per square meter. These areavailable commercially as photocopying base papers. Transparent papersmay also be used.

The compound is distributed throughout the entire support material.Under the action of heat, it creates a neutral or alkaline condition inthe light-sensitive coating. Suitable compounds are those whichinitially exhibit no neutral or alkaline reaction and which must beheated to become converted, as by decarboxylation or fission, intoproducts which exhibit neutral or alkaline characteristics. Thefollowing classes of compounds are suitable: monoamides or oligo-amidesof organic, aliphatic, monovalent or polyvalent carboxylic acids Withstraight or branched chains up to approximately fifteen carbon atoms,such as acetic acid, mono-, diand trichloroacetic acid; the diamides ofcarbonic acid, oxalic acid, fumaric acid or succinic acid; the amides ofacids which also hear one or several hydroxyl groups in the aliphaticchain, such as the amine of malic acid, tartaric acid, citric acid,hydroxy-acetic acid, hydroxy-butyric acid, and lactic acid; andcorresponding alkyl-ethers of these hydroxy carboxylic acids, such asthe amide of Z-methoxy-acetic acid. Urea is preferred, particularly whenused in combination with zinc chloride or trichloroacetic acid as statedbelow.

Additives which substantially improve the desired effect are smallamounts of acids, such a trichloroacetic acid, vinylphosphonic acid andorganic compounds which decompose through decarboxylation when heated toform anhydrides or ketones and thus lose their acidity. Other additivesare: beta-ketonic acids, such as pyroacemic acid; beta-hydroxy acids,such as lactic acid; and malic acid. These compounds have given goodresults in the case of amides whose decomposition temperatures arecomparatively high. Lower temperatures are afforded.

Incorporation of the substances creating the neutral or alkalineenvironment is preferably effected before all other process steps in thepreparation of the heat-developable copying paper. Incorporation ofthese substances into the support material when it is not yet dry hasproved particularly effective; for example, into a paper web during thepaper-making process in the paper machine. By this step, the penetrationof these substances into the support material is thorough. As a result,they are already present at the optimum position from which they canexert their action. Since they are not concentrated on the side whichsubsequently bears the light-sensitive mixture as in the usualprocesses, the shelf life of the copying material is substantiallyincreased by avoidance of the premature reaction between diazo compoundand coupling component.

The papers generally used have a strong sizing effect which inhibits thepenetration of water and aqueous solutions. Sizings of this nature areknown. This inhibitory effect of the papers sizing does not occur in thepapermaking process until the end of the drying of the paper. Byincorporating the substances creating the neutral or alkalineenvironment before the final drying of the raw paper, very smoothcomplete and uniform penetration is achieved. For this operation, allstations of the papermaking machine between web-formation andheat-drying are suitable. Suitable applicator devices are located in thefinal wet press and in the dry end of the paper machine. Rollerapplicators, such as the known sizing presses of various designs, arepreferred. Other applicators include air brushes, trailing blades, andsimilar coating devices. The amount may vary within large or widelimits; for example, approximately one to five mole parts, preferably1.5 to 3 mole parts theoretically necessary for the completeneutralization of the light-sensitive coating.

For special purposes, a second coating of small amounts of the substancemay be made as a separate coating on the front side, although this isnot necessary. The amounts of the second coating should be kept Withinnarrow limits, such as approximately 0.1 to 0.5 mole parts for thetheoretical neutralization of the other components in thelight-sensitive structure.

Over this second coating, or on the paper support which has not beenadditionally coated, the light-sensitive mixture is coated. The mixturecomprises the diazo and azo components and additives conventional indiazotype techniques.

Good results are achieved if the support material is provided with aprecoat which prevents or at least inhibits penetration of thelight-sensitive mixture into the support. These precoat properties mustapply only to the light-sensitive mixture. The precoat must not inhibitegress of the alkaline-reacting substances or fission products out ofthe support.

Suitable precoat materials are: cellulose derivatives such ascarboxymethyl cellulose, hydroxymethylethyl cellulose; alginates such assodium or ammonium alginate; organic condensates such asurea-formaldehyde or ureaglycerol resins; and many synthetic resins forthe surface treatment of paper such as water-soluble resins, polyamidederivatives, alkoxy methyl/ nylon, polyamine-epoxy resin, polymethylsiliconic acid sodium salt, finely-divided silicic acid of a particlesize between 0.2 and 10 microns, and rice starch or oat starch.Combinations of these materials have also proved suitable. Many of themsimultaneously improve contrast in the developed images.

In the case of the precoat materials, which are applied in the form oftheir soluble alkali metal salts or ammonium salts, care must be takento insure adequate neutralization. This can be done by adding a suitableamount of acid to the light-sensitive prepartion, by providing theprecoated material with an intermediate coating of an acid beforeapplying the light-sensitive coating, or by precoating with an aqueoussolution of an acid and applying the substance to be neutralized as afurther coating. It is also possible to acidify the precoat solutionbefore application.

Examples of agents which have proved especially suitable forneutralization are the aqueous solutions of trichloroacetic acid,hydrochloric acid, vinyl phosphonic acid, and the like. By controllingthe time interval between application of the neutralizable precoatmaterials and application of the neutradizing acid, or by choosingdiflerent drying temperatures after application of the precoat, it ispossible to regulate the depth of penetration of the precoat materialinto the mass of the paper.

This effect, which is caused by the application of these precoats, aidsthe maintenance of the good light sensitivity during lengthy storageperiods, since the light-sensitive substances are held fast near thesurface of the support material. In conventional diazotype coatings, afairly rapid decrease in light-sensitivity is observed with time.

All commonly known diazo and azo components may be used in alight-sensitive mixture. For example, 4-dimethylamino-benzene diazoniumchloride, 4 diethylamino-benzene diazonium chloride,4-N-ethyl-N-hydroxyethylamino-benzene diazonium chloride,4-morpholinobenzene diazonium chloride, and 4-pyrrolidino-3-br0mobenzenediazonium chloride are suitable diazo components Suitable couplingcomponents are: 2,3-dihydroxynaphthalene-6-sulfonic acid;2-hydroxy-(N-dimethyl)- naphthoic acid amide-(3);2-hydroxy-benzotriazole (1,2); 1,3,5- resorcyclic acid diethylamide;acetoacetic anilide; and l-(N-ethylamino)-3hydroxy-4-methyl-benzene.Mixtures of the individual components of the respective groups may alsobe used.

The light-sensitive mixture which is on at least one side of the supportmay contain additives. These additives may be classified into twogroups:

(1) Additives which serve as anti-yellowing agents, wetting agents,stabilizers, and the like; that is, additives which influence the diazoand azo components in order to retain their light sensitivity, couplingproperties, and their appearance as fully as possible, even afterlengthy storage. Additives of this group are: thiourea, glycerol,glycol, triethanolamine hydrochloride, saponin, zinc chloride, trisodiumnaphthalene-1,3,6-trisulfonate, and the like. In this group of additivesmay also be included agents which influence the application propertiesand surface properties of the mixture with respect to its processing.These are thickening and smoothing agents, such as gelatin,carboxymethyl cellulose, and polyvinyl acetate suspensions.

(2) Additives which create a neutral or alkaline condition by the actionof heat. Additives of this nature are the same as those described abovefor the substances in the mass of the support.

In many cases it has proved expedient to reduce the contact between thelight-sensitive preparation and the substances which exert an alkalineaction under heat and which are included in and incorporated into themass of the paper by precipitating the light-sensitive diazo compound ona finely-particled support material. This is accomplished by stirring asolution of the diazo compound into a suspension of polyvinyl acetateand silica particles, then precipitating the diazo compound withpolyvinyl phosphonic acid, and then coating the preheated papers asdescribed.

A two-component diazotype material thus prepared is capable of beingdeveloped by heat and also may be used in the conventional copyingprocesses. For example, in order to prepare a copy, the copying materialis covered with the original to be reproduced, and exposed in contact.After separation of the original, the copying material is exposed to abrief heat treatment. This may be effected for example by irradiationwith an infrared source under an infrared-absorbing material, such as anylon sieve which has been dyed black or an infrared-absorbing paper orfoil which is heat resistant up to 210 C. Treatment by pressing betweentwo heated rollers or by passing a hot air stream over the material alsoyields welldeveloped copies. In many cases it is expedient to supply theheat by contact from the back of the copying material. A marginallysharp copy with excellent covering power of the image area is formed.

Also in the preparation of the present heat-developable material,considerable advantages result from the fact that the coating on thefront side need consist only of the light-sensitive mixture by itself.In this way the constant contact between the light-sensitive mixture andthe activating substance is avoided. The result is very good shelf lifeof the copying material.

Substantial advantages over the prior art result also when a smallamount of activating substance is added to the light sensitive mixture,since this addition may be kept very small. The coating itself may becarried out in one single operation.

The copies prepared with the material according to the invention aredistinguished by great sharpness. Even when the finished copies arestored for an appreciable period, the support exhibits no effect, sothat legibility and contrast of the copies do not change.

The present invention is further illustrated by the following examplesWhich are intended not to limit the scope of the inventive concept.

EXAMPLE 1 A base paper suitable for diazotype techniques was impregnatedin a paper making machine by means of a sizing press at the dry end withan aqueous solution of the following composition:

Parts by weight Urea Zinc chloride 1.33 Citric acid 0.66 Water 91 Thepaper was then coated on one side with a 4% aqueous solution of vinylphosphonic acid, dried, and coated on the same side with a 1.2% aqueoussolution of the sodium salt of poly-methyl siliconic acid commerciallyavailable under the name Bautenschutzmittel BS/ 10. The paper web wasdried and then coated on the same side with an aqueous solution of thefollowing composition:

Parts by weight Trichloroacetic acid 3.2 Tartaric acid 0.2

2,3 -'dibydroxy-naphthalene-6-sulfonic acid (sodium salt) 4.0Nap-hthalene-1,3,6-trisrulfonic acid (sodium salt) 7.0 4-dimethylalmino-benzene diazonium chloride 2.0 Zinc chloride 1.,5 Urea1.5 Gelatin 0.09 Saponin 0.04 Water 75 The sensitized copying materialwas exposed under an original and developed by contact with heatedrollers to yield contrasty, blue-colored copies having excellent shelflife, even under moist climatic conditions.

EXAMPLE 2 A base paper suitable for diazotype techniques was impregnatedon the final wet press in the paper machine with the following solution:

Parts by weight Urea Zinc chloride 2 Citric acid 1 Water 88 The materialthus prepared was coated on one side with the following solution:

Parts by weight Triohloroacetic acid 1.2 Tartaric acid 0.2

Thiourea 4.0

The copying material was exposed under an original and developed by heatto yield contrasty, blue-colored copies with good keeping qualities.

EXAMPLE 3 A suitable base paper as described in Example 1 wasimpregnated on the introducing or offset press of the paper machine withthe following solution:

Parts by weight Lactic acid amide 30 Pyroracemic acid 10 Water 80 Thematerial thus obtained was coated on one side with the followingsolution:

Parts by weight Triohloroacetic acid 1.0 Tartaric acid 0.2 2,3-dihydroxy-naphthalene-G-sulfonic acid (sodium salt) 4.0 'Ilhiourea 4.0Naphthalene-1,3,6-trisulfonic acid (sodium salt) 7.0 Urea 4.0 4 N ethylN hydroxyethylamino benzene diazonium chloride 2.4 Gelatin 0.09 Saponin0.04 Water 90 When developing by heat was elfectted, a blue-colored copywas obtained.

EXAMPLE 4 A base paper as described in Example 1 was impregnated on thesizing press of the paper machine with the following solution:

Parts by weight Urea 10 Zinc chloride 1.33 Citric acid 0.66 Water 91 Thematerial thus prepared was coated on one side with an aqueous solutionof 7.5% polyvinyl phosphonic acid, dried, and coated on the same sidewith a 3% aqueous solution of the sodium salt of polymethyl siliconicacid commercially available under the name Bautenschutzmittel BS/ 10.The paper web was then dried and coated on the same side with an aqueoussolution of the followmg composition:

Parts by weight Trichloroacetic acid 2.0 Tartaric acid 0.2Naphthalene-1,3,6-trisulfonic acid (sodium salt) 7.0 Thiourea 4.0 2,3-dihydroxy-naphthalene-6-sulfonic acid (sodium salt) 4.0 Lactic acidamide 10.0 Zinc chloride 0.5 4 N ethyl N hydroxyethylamino benzenediazonium chloride 2.4 Gelatin 0.09 Saponin 0.04 Water When developingby heat was elfected after exposure, a dark blue color was obtained.Copying material had excellent shelf life.

EXAMPLE 5 A base paper as described in Example 1 was impregnated on theintroducing or oflF-set press of the papermaking machine with thesolution described as follows:

Parts by weight Urea 15 Zinc chloride 2 Citric acid 1 Water 88 Thematerial thus obtained was coated on one side with the followingsolution:

Parts by weight Trichloroacetic acid 2.0 Tartaric acid 0.2

2,3 dihydroxy-naphthalene-6-sulfonic acid (sodium salt) 4.0Naphthalene-1,3,6-trisulfonic acid (sodium salt) 7.0 'Ilhiourea 4.0

Tartaric acid diaimide 10.0 Zinc chloride 0.5

4 N ethyl N hydroxyethylamino benzene diazonium chloride 2.4 Gelatin0.09 Saponin 0.04 Water 80 When developing was effected by heat, verygood blue copies of the original were obtained.

EXAMPLE 6 A base paper as described in Example 1 was impregnated on theintroducing or off-set press of the papermaking machine with thefollowing solution:

Parts by weight Urea 15 Trichloroacetic acid 3 Water 85 The materialthus obtained was then coated on one side with a 5% aqeuous solution toa polyamide-epoxide resin commercially available under the name Nadavin.After drying, coating was carried out with a solution of the followingcomposition:

Parts by weight Trichloroacetic acid 1.0 Tartaric acid 0.22,3-dihydroxy-naphthalene-6-sulfonic acid (sodium salt) 4.0 Thiourea 4.0Naphthalene-1,3,6-trisulfonic acid (sodium salt) 7.0 Urea 2.5 Zincchloride 0.5 4-dimethylamino-benzene diazonium chloride 2.4 Gelatin 0.09Saponin 0.04 Water 80 After exposure, there was obtained by heating, avery contrasty, blue copy of the original.

EXAMPLE 7 A base paper as described in Example 1 was impregnated on thefinal wet press of the paper machine with the following solution:

Parts by weight Urea 15 Zinc chloride 2 Citric acid 1 Water 88 Thematerial thus prepared was coated on one side with an aqueous solutionof 3% of the sodium salt of polymethyl siliconic acid commerciallyavailable under the name Bautenschutzmittel BS/ and 1% sodium alginate.After drying, the following solution was applied to the same side of thepaper:

Parts by weight Tartaric acid 1.5 2,3-dihydroxy-naphthalene-6-sulfonicacid (sodium salt) 4.0 Thiourea 4.0 Naphthalene-1,3,6-trisulfonic acid(sodium salt) 4.0 4-dimethylamino-benzene diazonium chloride 2.4 Gelatin0.09 Saponin 0.04 Urea 5.0

Water 80 After exposure, there was obtained by heating, a good, darkblue copy of the original.

EXAMPLE 8 A base paper as described in Example 1 was impregnated in thepaper machine by means of a sizing press inside the dry end with anaqueous solution of the following composition:

Parts by weight Urea 10.0 Urea-glycerol resin prepared by meltingtogether and Parts by weight heating for one hour at 120 C. equal partsof urea and glycerol 8.5 Water 82 The material thus obtained was coatedon one side with the following solution:

Parts by weight Tartaric acid 0.2 2,3-dihydroxy-naphthalene-6-sulfonicacid (sodium salt) 4.0 Thiourea 4.0 Naphthalene-1,3,6-trisulfonic acid(sodium salt) 4.0 4-dirnethylamino-benzene diazonium chloride 1.7Saponin 5.0 Gelatin 0.09 Water 85 After exposure, when developing byheat was effected, a blue copy of the original was obtained.

EXAMPLE 9 A transparent base paper suitable for diazotype techniques wasimpregnated in the paper machine by means of an air brush applicatorinside the dry end with the following solution:

Parts by weight Urea 10 Zinc chloride 1.33 Citric acid 0.66 Water 91 Thematerial thus obtained was coated on one side with a solution of 7.5%methoxymethyl poly-e-caprolactam in 70% methanol and, after drying, thefollowing solution was applied to the same side of the paper:

Parts by weight Trichloroacetic acid 3.2 Tartaric acid 0.2 2,3-dihydroxynaphthalene-6-sulfonic acid (sodium salt) 4.0 Thiourea 4.0Naphthalene-1,3,6-trisulfonic acid (sodium salt) 7.0 Urea 10.04-dimethylamino-benzene diazonium chloride 2.0 Zinc chloride 1.5 Gelatin0.09 Saponin 0.04 Water After exposure, when developing by heat waseffected, a blue copy of the original was obtained.

EXAMPLE 10 A base paper was treated on the sizing press in the papermachine with the following solution:

Parts by weight Urea 15 Zinc chloride 2 Citric acid 1 Water 88 Thematerial thus obtained was coated with an aqueous suspension prepared inthe following manner:

4 parts by weight of a finely-particled silicic acid with a grain sizedistribution lying mainly between 1 and 10 microns were suspended in 70parts by volume of a 1.5% aqueous solution of the sodium salt of apolymethyl siliconic acid commercially available under the nameBautenschutzmittel BS/ 10. 20 parts by volume of a 20% by weightsuspension of a polyvinyl acetate copolymer commercially available underthe designation Mowilith DMC No. 2 were then added. To the suspensionthus obtained there was added, gradually and with vigorous stirring, 10parts by volume of a 10% aqueous soluiton of monomeric vinylphosphonicacid, and the whole then stirred briskly for an hour.

After drying, the pretreated paper was coated on the same side with asolution of the following composition:

Parts by weight The paper thus prepared was distinguished byparticularly good shelf life and high contrast. After exposure under atransparent original, it was developed by heating up to 160 to 170 C. Agood blue-colored positive copy of the orginal was obtained.

It is evident that the described examples are capable of many variationsand modifications. All such variations and modifications are to beincluded within the scope of the present invention.

What is claimed is:

1. A heat-developable reproduction material which comprises:

a paper support impregnated in the paper-making process with a mixtureof urea and urea-glycerol resin; and

a light-sensitive diazo coating comprising a diazonium compound, an azocoupling component and an acid stabilizer on at least one side of thesupport, said I coating being developable by the action of heat on themixture of urea and urea-glycerol resin.

2. A heat-developable reproduction material which comprises:

a paper support impregnated in the paper-making process with a mixtureof lactic acid amide and pyroracemic acid, which mixture, when heated,is activated to generate an alkaline environment; and

a light-sensitive diazo coating comprising a diazonium compound, an azocoupling component and an acid stabilizer on at least one side of thesupport, said coating containing urea and being developable by theaction of heat on the mixture of lactic acid amide and pyroracemic acidand the urea.

3. A heat-developable reproduction material which comprises:

a paper support impregnated in the paper-making process with urea; and

a light-sensitive diazo coating comprising a diazonium compound, an azocoupling component and an acid stabilizer on at least one side of thesupport, said coating containing tartaric acid amide and beingdevelopable by the action of heat on the urea and the tartaric acidamide.

4. A heat-developable reproduction material which comprises:

a paper support impregnated in the paper-making proc ess with urea;

a layer of polymethyl siliconic acid sodium salt and sodium alginate;and

a light-sensive diazo coating comprising a diazonium compound, an azocoupling component and an acid stabilizer on the layer, said coatingcontaining urea and being developable by the action of heat of the urea.

5. A heat-developable reproduction material which comprises:

a transparent paper support impregnated in the paper making process withurea; a layer of methoxy methyl poly-e-caprolactam; and alight-sensitive diazo coating comprising a diazonium compound, an azocoupling component and an acid stabilizer on the layer, said coatingcontaining urea and being developable by the action of heat on the urea.6. A heat-developable reproduction material which comprises:

a paper support impregnated in the paper-making process with urea; alayer of silicic acid, polymethyl siliconic acid sodium salt, andpolyvinyl acetate; and a light-sensitive diazo coating comprising adiazonium compound, an azo coupling component and an acid stabilizer onthe layer, said coating containing urea and being developable by theaction of heat on the urea. 7. A heat-developable reproduction materialwhich comprises:

a paper support impregnated in the paper-making process with urea; afirst layer of vinyl phosphonic acid coated on at least one side of thesupport; a second layer of polymethyl siliconic acid sodium salt coatedon the first layer; and a light-sensitive diazo coating comprising adiazonium compound, an azo coupling component and an acid stabilizer onthe second layer, said coating containing urea and being developable bythe action of heat on the urea. 8. A heat-developable reproductionmaterial which comprises:

a paper support impregnated in the paper-making process with urea; afirst layer of polyvinyl phosphonic acid coated on at least one side ofthe support; a second layer of polymethyl siliconic acid sodium saltcoated on the first layer; and a light-sensitive diazo coatingcomprising a diazonium compound, an azo coupling component and an acidstabilizer on the second layer, said coating containing lactic acidamide and being developable by the action of heat on the urea and thelactic acid amide.

References Cited UNITED STATES PATENTS 2,617,727 11/1952 Slifkin 96-753,159,487 12/1964 Krieger et a1. 96--91 XR 3,169,067 2/ 1965 Berman etal. 96-91 3,312,551 4/1967 Sus 96-49 XR 3,076,707 2/ 1963 Lawton et al.96-49 XR 3,255,007 6/1966 Kosar 96--91 XR FOREIGN PATENTS 12,096 7/1963Japan. 597,615 5/ 1960 Canada. 907,724 10/ 1962 Great Britain. 909,49110/ 1962 Great Britain. 931,668 7/1963 Great Britain. 1,249,913 11/1960France.

NORMAN G. TORCHIN, Primary Examiner.

C. BOWERS, Assistant Examiner.

1 US. Cl. X.R. 96--49

